This invention is a low-cost, recyclable, easily replaceable vacuum or thermoformed insert or liner for mushroom-growing trays that are assembled or formed of wood or composites of wood or recyclable materials that may be subject to deterioration by rot or use.
It is common practice in the mushroom growing industry to grow mushrooms in large wooden trays. Typically, mushroom-growing trays have commonly been made out of either oak or pressure-treated wood.
Wood is fairly durable and inexpensive however there may also have been an effort to manufacture the mushroom trays from other materials such as pressboard or recycled cardboard or paper. The typical wooden mushroom trays are tough enough to withstand the forces incurred when transported by forklift trucks, and a common wood used to fabricate them is oak. Typically, wooden mushroom trays are stacked to create multiple levels of trays within the same amount of floor space, as one tray would occupy. By stacking the growing trays in tiers, a larger number of mushrooms in a concentrated area can be cultivated.
However, the use of wooden trays or the like has several disadvantages. For example, wooden trays are difficult to clean at the end of each growing cycle. During and after the cleaning process, the porous wood becomes moisture-swollen and its fibrous surface traps spent compost material. Since the growing medium remains embedded in the wood fibers after the tray has been emptied, the wood begins to rot, which weakens the overall structure of the tray, thereby shortening its useful life. Another undesirable feature is that detrimental molds may propagate in the new growing medium, causing contamination that could result in diminished yield for any particular crop.
Alternate mushroom tray designs (metal, plastic, and composite) have been developed in an attempt to overcome the above-mentioned disadvantages.
The invention disclosed in U.S. Pat. No. 5,040,328 to Coon discloses a mushroom tray fabricated from a plastic that has downward-opening channels and is secured to a support structure made of corrosion-resistant material. Following the assembly of this unit, this tray is filled with mushroom growing material. There is also a plurality of clips to secure the plastic tray to the aluminum support. The ""328 patent disclosing the mushroom tray describes a non-porous surface in its construction, thereby eliminating wood rot or mold growth in the structure. The ""328 reference apparently is intended to provide a mushroom tray that will possess the requisite strength to withstand resulting vertical load and associated forces when multiple trays are stacked, as well as other forces endured during transportation or movement of the trays. In order to overcome some disadvantages of mushroom trays such as that described in the ""328 reference, U.S. Pat. No. 6,016,627, to Nobile discloses a stackable composite mushroom-growing tray. The ""627 reference discloses a structure fabricated out of a glass-reinforced plastic composite. The structure of the tray is uniquely molded to include a bottom surface having graduated height ribs and corrugations extending perpendicular to the ribs to improve rigidity. There is also a plurality of holes and specially molded recesses for the spacers necessary for stacking multiple trays. A disadvantage of this type of system may be the expense of manufacture due to the elaborate materials and details that need to be molded into the structure, which are accomplished through use of an expensive mold.
Accordingly, there is a need for a more cost-effective method to improve the clean-out capabilities and increase the lifespan of wooden mushroom-growing trays that are formed of various wood materials or the combination thereof from recycled, manufactured, or remanufactured biodegradable materials. Additionally, a benefit is that, when used in trays constructed with chemically pressure-treated wood, the tray liner will provide a protective layer between the treated wood tray and the growing medium. The U.S. Environmental Protection Agency (EPA) recently announced that wood treated with CCA (chromated copper arsenate) will be banned from residential use by January 2004. If this ban is extended to the food-growing industry, the liner may prove to be highly beneficial in protecting untreated wood growing trays (or growing trays constructed of biodegradable materials) from the wood-decaying effects of the growing medium. This will be shown in the following detailed specification of the present invention that provides an easily manufactured, protective and cost effective tray liner for mushroom-growing trays.
The present invention concerns a tray liner that is insertable into a mushroom growing tray. The tray liner is formed as a rectangular base member with a periphery of upstanding sidewalls joined to a base portion. There is a notched section located at each corner of the rectangular base member to accommodate the upstanding frame member located at each corner of the wooden mushroom-growing tray. The notch section has a contiguous wall that is joined with the periphery of upstanding sidewalls and the base member.
This invention has advantages over the prior art by providing an inexpensive, replaceable, and fully recyclable trayxe2x80x94insert (hereinafter referred to as xe2x80x9ctray linerxe2x80x9d) for existing wooden mushroom growing trays. Once installed, the tray liner could remain in a wooden mushroom-growing tray for the life of that tray which Will extend the usefulness of such growing trays. The tray liner as conceived in the present invention could even be reused in a new wooden tray when the original wooden tray has come to the end of its useful life.
A feature of the present invention is that the smooth radius corners that result from this one-piece tray liner as manufactured eliminates or reduces the sharp corners of the wood constructed tray. The manufacturing process is simple, and provides a smooth textured mushroom-tray liner that is easy to fabricate, handle and install. The smooth surface of the material of the tray liner facilitates the cleaning of spent material such as old growing medium from the lined wooden mushroom-growing tray at the end of each growing cycle. One of several alternative embodiments of the present invention is included to provide a replaceable tray liner that comprises a plurality of similarly shaped sections that may be installed in sections to a mushroom-growing tray. This alternate design provides additional lower manufacturing and/or shipping costs and easier handling for the mushroom grower.